• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.185-195
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• 2015

Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.89-94
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• 2010

액체로켓 기체공급계는 추진제를 요구되는 유량, 온도, 압력으로 엔진에 공급하여야 한다. 이를 위한 정상상태의 공급특성은 기존의 열역학 및 열전달, 유체역학 이론을 적용하여 해석하며 방법론이 잘 정립되어 있다. 발사체의 비행 중에 발생하는 탱크와 공급배관에서의 추진제의 진동은 정상상태의 공급특성을 변하게 하며 추진제공급 요구조건을 만족시키지 못하게 한다. 이러한 진동을 발생시키는 것으로서 발사체의 가속도로 인한 슬로싱 및 엔진의 추력섭동에 의해 배관 내 추진제가 진동하는 포고 불안정이 있다. 포고와 슬로싱에 의한 발사체 제어와 구조측면에서 미치는 영향에 대해서는 기존에 많은 연구가 있으나 추진제 공급특성에 미치는 영향에 대해서는 잘 알려져 있지 않다. 본 연구에서는 추진제의 진동이 엔진으로의 추진제 공급에 미치는 영향을 기존 자료를 이용하여 살펴보고 진동을 제어하기 위한 기구를 살펴본다.

• 한국초지조사료학회지
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• 제36권4호
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• pp.381-386
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• 2016

The objective of this research was to evaluate the effects of two different feeding systems on blood metabolites in Holstein heifers and analyze the economic impacts of the feeding systems. The following two experiments were conducted to investigate the effects of feeding system on blood metabolite changes in Holstein heifers and analyze the economic impacts of the two systems. In experiment 1, the effects of two different feeding systems on cortisol, progesterone, and estradiol in Holstein heifers were examined. In experiment 2, the effects of two different feeding systems on the body weights of Holstein heifers and profitability of the two feeding systems were studied. Results showed that the pasture-raised heifers showed significantly decrease in the levels of blood cortisol (p<0.05) and increases in the levels of progesterone and estradiol (p>0.05) when compared with heifers raised in indoor feeding system. The average daily gain was significantly higher (p<0.05) in indoor-raised heifers (0.73 kg/day) as compared to pasture-raised heifers (0.58 kg/day). Also, 25.2% more profits were obtained from the pasture feeding system as compared to the indoor feeding system. These results together would be useful in the investigation of feeding system and growth performance in dairy cattle.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.451-455
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• 2010

In this study, the various supply system of LRE such as a feed-line, an elbow, and an orifice as a part of integrated analyzing has been combined to develop the performance analysis program. Computational analysis has been used to compare the results and to verify the validity and limitation conditions of the performance analysis program by changing orifice positions.

• Asian-Australasian Journal of Animal Sciences
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• 제16권7호
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• pp.1015-1019
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• 2003

A 50 day feeding trial was conducted with White Leghorn (WL) laying hens, 42 weeks old, to determine if feeding of varying levels of aflatoxin (AF), ochratoxin A (OA) or their combinations has any effect on their performance and egg quality parameters. Feeding of $T_4$, $T_7$, $T_8$, $T_9$ and $T_10$ caused significant reduction in feed intake of hens. Hen day egg productions were significantly reduced at all the levels of toxins except 0.5 ppm of AF. Maximum reduction in egg production was noticed at 2 and 4 ppm of AF and OA, respectively. Average body weight and egg weight were not affected by toxin feeding. The feed efficiency in terms of net feed efficiency and feed consumed per dozen egg produced was significantly reduced at higher levels of both the toxins and their combinations. Feed consumption for production of 1 kg egg mass remained uninfluenced due to aflatoxin feeding whereas significant increase in the value of the same was noticed at 4 ppm level of OA and combination of 1 and 2 ppm of AF and 2 and 4 ppm of OA ($T_9$ and $T_10$), respectively. Various levels of OA (1-4 ppm) and all the combination of two toxins ($T_8$, $T_9$ and $T_10$) significantly altered the shape index of eggs in laying hens. The shell thickness was significantly reduced by higher level of AF (2 ppm), OA (2 and 4 ppm) and their combination. Albumen index, Haugh Unit and yolk index remained unchanged due to incorporation of toxins in the diet. It is concluded that AF, OA either singly or in combination at higher levels could depress the performance in terms of egg production and feed efficiency significantly. The egg quality parameters i.e. shape index and shell thickness were also significantly affected.

• 재활치료과학
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• 제3권2호
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• pp.49-57
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• 2014

목적 : 본 연구는 조산아를 대상으로 한 구강자극프로그램 실시가 구강식이수행에 영향을 미치는지를 알아보고자 하였다. 연구방법 : 연구대상은 조산 (25주)로 출생한 아동 1명이었으며, 총 4주간 연구를 진행하였다. 중재방법은 구강자극프로그램으로 뺨, 윗입술, 아랫입술, 윗입술과 아랫입술의 커브, 윗잇몸, 아랫잇몸, 뺨의 내부, 혀의 측면, 혀의 중간을 손가락으로 눌러주며 자극을 주는 9가지 활동으로 구성되었다. 구강식이수행 요인으로는 체중, 하루에 섭취하는 우유의 양, 한 번에 먹는 우유의 양, 한 번 우유 먹을 때 걸리는 시간으로 측정하였다. 각 요인은 매주, 시간에 따른 변화를 측정하였다. 결과 : 중재 실시 후, 대상자의 체중이 증가하였으며 하루에 먹는 우유의 양과 한 번에 먹는 우유의 양도 증가하였다. 한 번 우유를 먹을 때 걸리는 시간은 감소하였다. 결론 : 구강자극프로그램은 조산아의 구강식이 수행을 향상시킬 수 있는 방법이며, 따라서 가정과 치료환경에서 적절히 활용할 수 있을 것이다.

• 한국공작기계학회논문집
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• 제16권2호
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• pp.50-56
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• 2007

Wire forming machine is widely used in industries to make a variety of wire products such as coil springs and links. Along with the rapid development of CNC technologies, the usage of wire forming machine varies from single-purpose machinery to universal CNC machinery. Rotating the wires while feeding them simultaneously, we can improve the performance of the machines with aspects of efficient tooling and complicated geometric forming. In this study, a new gear train is developed for the control of both feeding and rotating wires independently at the same time. The developed mechanism has many benefits as following, making more complicated geometric and precision products, easier tooling, and simpler programming.

• 한국가금학회지
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• 제21권2호
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• pp.101-111
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• 1994

From the observations of dietary self-selection by growing pullets, step-up protein or reverse protein and single-stage low protein pullet feeding systems were developed. They offered another pullet feeding concept that appears to control the body weight effectively and to reduce the consumption of feed and nutrients without impairment of subsequent laying performance. It is obvious from the feed and nutrient consumption pattern of layers fed diets for self-selection of energy, protein and calcium that they have a daily cyclic requirement rather than a constant requirement for nutrients. It seems that a practical self-selective feeding system is needed to meet the daily cyclic requirement for nutrients without consuming an excess of energy and protein at certain times of the day as compared to the complete or single diet where layers have to consume extra energy and protein in the afternoon when they have a specific appetite mainly for calcium.

• Asian-Australasian Journal of Animal Sciences
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• 제13권6호
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• pp.802-810
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• 2000

A total of 120 finishing crossbred pigs ($Landrace{\times}Large$ $White{\times}Duroc$) with equal numbers of barrows and gilts weighing 58.5 kg body weight were used in a feeding trial, and 6 pigs (three of each sex) were used in a metabolic trial to investigate the effect of phase feeding. Finishing period was divided into two phases and 4 different diets were fed for those periods. Growth performance was not significantly different among treatments within the same sex. This result showed that 16% crude protein for early finishing period and 14% crude protein diet for late finishing period should be optimum. During the early finishing period, only feed intake was significantly different between sexes (p<0.01), but in late finishing period daily weight gain (p<0.001) and feed intake (p<0.01) of barrows were significantly higher than those of gilts. During the early finishing period, digestibilities of dry matter, protein and phosphorus were significantly higher in gilts than in barrows (p<0.05). However, there was no treatment effect within same sex during the early and late finishing period. During early finishing period, excretion of N of pigs fed 16% CP diet in early and 14% CP diet in late-finishing period was less than that of pigs fed 17% CP diet in early and 15% CP diet in late-finishing period (p<0.05), but the difference was not significant. During the late finishing period, N excretion with two phase feeding was reduced by 8.5% compared with single feeding. In gilts, total cost reduction by two phase feeding compared to single feeding was 9.1%, but in barrows it was just 3.19%. Relative margin increased with two phase feeding by 2.5% in gUts and 0.2% in barrows. There was a tendency that backfat thickness at 10th rib of gilts was thinner than that of barrows (p>0.05). Within the same sexes, there was no treatment effect on back fat thickness (p>0.05). Carcass grade was improved by two phase feeding compared to single feeding. Carcass grade of gilts was significantly better than that of barrows (p<0.001). From this results, it is concluded that finishing pigs could be fed two-phase diets to improve profit and reduce pollution.

• Asian-Australasian Journal of Animal Sciences
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• 제26권7호
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• pp.995-1002
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• 2013

The effect of conjugated linoleic acid (CLA) feeding on growth performance and fatty acid profiles in thigh meat of broiler chicken was investigated using meta-analysis with a total of 9 studies. Overall effects were calculated by standardized mean differences between treatment (CLA fed) and control using Hedges's adjusted g from fixed and random effect models. Meta-regression was conducted to evaluate the effect of CLA levels. Subgroups in the same study were designated according to used levels of CLA, CP levels or substituted oils in diets. The effects on final body weight, weight gain, feed intake and feed conversion ratio were investigated as growth parameters. Total saturated and unsaturated fatty acid concentrations and C16:0, C18:0, C18:2 and C18:3 concentrations in thigh meat of broiler chicken were used as fatty acid profile parameters. The overall effect of CLA feeding on final weight was negative and it was only significant in fixed effect model (p<0.01). Significantly lower weight gain, feed intake and higher feed conversion ratio compared to control were found (p<0.05). CLA feeding on the overall increased total saturated fatty acid concentration in broilers compared to the control diet (p<0.01). Total unsaturated fatty acid concentration was significantly decreased by CLA feeding (p<0.01). As for individual fatty acid profiles, C16:0, C18:0 and C18:3 were increased and C18:2 was significantly decreased by CLA feeding (p<0.01). In conclusion, CLA was proved not to be beneficial for improving growth performance, whereas it might be supposed that CLA is effective modulating n-6/n-3 fatty acids ratio in thigh meat. However, the economical compensation of the loss from suppressed growth performance and increased saturated fatty acids with the benefit from enhanced n-6/n-3 ratio should be investigated in further studies in order to propose an appropriate use of dietary CLA in the broiler industry.